This is the third submission of an R34 to conduct a formative randomized controlled trial of CBT for ADHD in adolescents who are treated by medications and still have significant residual symptoms. ADHD in adolescence is a prevalent, distressing, and interfering condition. Although medications are efficacious in treating ADHD in adolescents, typically significant residual symptoms remain after psychopharmacotherapy. Unlike other mental health problems with a similar prevalence (e.g. anxiety and depression), there is a lack of psychosocial treatments for adolescents with ADHD. The proposed project is to complete stages 2 and 3 of intervention development as outlined by NIMH PA 06-248, adapting our cognitive behavioral therapy for residual ADHD in adults to the adolescent population. Intervention. The intervention is based on existing conceptual models of ADHD, our work with adults, and an open phase pilot with adolescents. In our previous work, we have demonstrated that our manualized CBT for residual ADHD in adults was more effective than continued medications alone. The treatment is now being compared to relaxation with educational support in the context of a full scale randomized controlled trial in adults (MH069812). The CBT involves four core modules and one optional module. The core modules in the adult intervention are 1) psycho education and organizing/planning;2) coping with distractibility, 3) adaptive thinking, and 4) involvement of a significant other (in the adult study, one's partner or spouse). The optional module is on utilizing the previously learned skills for coping with procrastination. For adolescents, we have adapted this approach to include check-in time with parents, innovative material that caters to adolescents (i.e. internet / cell phones), a focus on schoolwork and chores, and a decreased focus on cognitive restructuring. Design. Forty adolescents with ADHD who are stabilized on medications but still show clinically significant residual symptoms will be block randomized by sex and ADHD severity to either CBT or a wait-list control. Self-report, parent-report, teacher report, and independent assessor (who will be blind to treatment condition) data will be used as outcomes. Environment/feasibility. The PI team, as part of the CBT and Behavioral Medicine Programs at MGH, has extensive experience conducting CBT outcome studies. Collaborating with the pediatric psychopharmacology unit at MGH, we have access to potential participants through one of the largest pediatric psychopharmacology services in the country. This unit sees hundreds of adolescents with ADHD per year, all of whom is treated with medications and would be eligible for the planned trial.